Conventionally, a refrigerator includes a storage chamber for storing the food therein. The refrigerator regulates a compartment inside temperature by using a cooling cycle apparatus (comprised of a compressor, condenser, capillary tube, and evaporator), and stores the foodstuffs received in the compartment to keep the foodstuffs fresh for a long time.
In recent times, following the trend for large-sized storage compartments for storing great quantities of foodstuffs, a refrigerator having such a large-sized storage chamber is well known in the art. Such a refrigerator includes a freezing compartment as well as the refrigerating compartment with a large capacity. The refrigerator further includes a plurality of evaporators and fans, and thus respectively provides cool air to the freezing and refrigerating compartments.
In such a conventional refrigerator, the freezing compartment and the refrigerating compartment are separated from each other. An evaporator and fan are mounted on a rear wall of the freezing compartment, and another evaporator and another fan are mounted to a rear wall of the refrigerating compartment.
Referring to a conventional large-size refrigerator depicted in FIG. 1, a compressor 27 is connected in series to a freezing compartment temperature regulator 10 and a defrosting timer 11. A starting condenser C1 connected to a front end of the compressor 27 provides a starting current from a power-supply. An operation condenser C2 provides an operation current after a starting operation. A positive temperature coefficient (PTC) relay 26 provides a starting current to the compressor 27. An overload relay 28 prevents an abnormal temperature rising and overcurrent of the compressor 27. A compressor cooling fan motor 25 adjacent to the compressor 27 is driven with the compressor 27 in order to circulate outside air and hence to cool the compressor 27.
A first terminal al of the defrosting timer 11 is connected to a freezing compartment fan motor 21 and a refrigerating compartment temperature regulator 22. A refrigerating compartment fan motor 24 is connected to a first terminal b1 of the refrigerating compartment temperature regulator 22. The freezing compartment fan motor 21 and the refrigerating compartment fan motor 24 respectively circulate cool air generated by the freezing compartment evaporator and the refrigerating compartment evaporator respectively to the freezing compartment and the refrigerating compartment.
A second terminal b2 of the refrigerating compartment temperature regulator 22 is connected to a metal heater 23. The metal heater 23 generates a slight heat. By this slight heat, the temperature regulator 22 is compensated a peripheral low temperature.
A door switch 20 is directly connected to a power-supply input terminal AC. The door switch 20 turns on a first lamp 18 when opening a refrigerating compartment door, and turns on a second lamp 19 when opening a freezing compartment door. The door switch 20 cuts off power applied to the fan motors 21 and 24 simultaneously with the turning on of the lamps 18 and 19.
In a defrosting operation, a synchronous motor M1 of a defrosting timer 11 is driven, and thus the synchronous motor M1 is connected to the second terminal a2. A first defrosting heater 14 serially connected to a first temperature fuse 13 and a second defrosting heater 17 serially connected to a second temperature fuse 16 generate heat. A first bimetal thermostat 12 is connected to the first temperature fuse 13. A second bimetal thermostat 15 is connected to the second temperature fuse 16. These thermostats 12 and 15 sense a surface temperature of a freezing compartment evaporator and of a refrigerating compartment evaporator. If the first and second bimetal thermostats 12 and 15 are turned off because they arrive at a defrosting release temperature, power is cut off so that the defrosting operation of the first defrosting heater 14 and the second defrosting heater 17 is terminated.
In the aforementioned refrigerator, the refrigerating compartment temperature regulator 22 for controlling the refrigerating compartment temperature is dependent upon the freezing compartment temperature regulator 10. Therefore, cooling of the refrigerating compartment is not achieved even if the refrigerating compartment temperature is high when the freezing compartment temperature regulator 10 is turned off.
Referring to FIG. 2, in the case where a refrigerator is initially driven after receiving power from a power-supply, the temperatures of the freezing and refrigerating compartments are higher than each set temperature. At this time, under the condition that the freezing compartment temperature regulator 10 is connected to the first terminal b1 and that the defrosting timer 11 is connected to the first terminal a1 so that the compressor 27 and the freezing compartment fan motor 21 are driven, cool air generated by the freezing compartment evaporator is circulated toward the inside of the freezing compartment. In addition, with the refrigerating compartment temperature regulator 22 connected to the first terminal b1, cool air generated by the refrigerating compartment evaporator is circulated toward the inside of the refrigerating compartment.
If the freezing compartment temperature is below the freezing compartment set temperature while performing a cooling operation for each compartment, the freezing compartment temperature regulator 10 goes to an off state so that the power is cut off, and therefore the compressor 27 and the freezing compartment fan motor 21 are turned off. In a period R1 wherein a cooling operation is still required because a temperature of the refrigerating compartment is still higher than the refrigerating compartment set temperature, the refrigerating compartment temperature regulator 22 is connected to the first terminal b1. However, with the power cut off, the refrigerating compartment fan motor 24 is stopped. As a result, further circulation of cool air toward the inside of the refrigerating compartment is stopped, so that the cooling operation of the refrigerating compartment is inefficiently effected.
If a defrosting operation starts, a defrosting timer 11 is connected to the second terminal a2 by a driving of the synchronous motor M1. The first and second defrosting heaters 14 and 17 are then driven so that a defrosting operation is performed to remove frost formed on the freezing compartment evaporator.
If the defrosting operation is terminated, the defrosting timer 11 is connected to the first terminal a1 by a driving of the synchronous motor M1. This results in the compressor 27 and the freezing compartment fan motor 21 being driven, cool air being applied to the freezing compartment, and a cooling operation of the freezing compartment being performed. At this time, if a refrigerating compartment temperature regulator 22 is connected to the first terminal b1, the refrigerating compartment fan motor 24 is driven so that a cooling operation of the refrigerating compartment is performed.
When a temperature of the freezing compartment becomes lower than the freezing compartment set temperature while performing the cooling operation of the freezing compartment, the freezing compartment temperature regulator 10 is changed to an off state and the power is cut off. Therefore, the compressor 27 and the freezing compartment fan motor 21 are stopped and the refrigerating compartment fan motor 24 cannot be driven. In this case, if the refrigerating compartment temperature maintains a proper temperature, there is no problem with the cooling operation of the refrigerating compartment. However, if the refrigerating compartment temperature is higher than the refrigerating compartment set temperature (for example, where food is initially stored in the refrigerating compartment), in the period R2 wherein a cooling operation of the refrigerating compartment is required, the refrigerating compartment temperature regulator 22 is connected to the first terminal b1 but the refrigerating compartment fan motor 24 is without power. This results in an inefficient cooling operation of the refrigerating compartment.
As described above, in the conventional refrigerator, driving of the refrigerating compartment fan motor is determined by the freezing compartment temperature regulator which is turned on or off in response to the temperature of the freezing compartment. Thus, the cooling operation of the refrigerating compartment is dependent upon the cooling operation of the freezing compartment, which results in: an inefficient cooling operation of the refrigerating compartment, a higher than desired temperature of the refrigerating compartment, an increase in the total time required for a cooling operation of the refrigerating compartment, and a decreasing operation efficiency.